Fulchini, F, Zafar, U, Hare, C et al. (4 more authors) (2017) Relationship between Surface Area Coverage of Flow-Aids and Flowability of Cohesive Particles. Powder Technology, 322. pp. 417-427. ISSN 0032-5910
Abstract
Poor and inconsistent flow of cohesive powders is a major issue in powder processing. A common solution is to coat the surfaces of the cohesive particles with finer particles, referred to as flow-aids. Such particles adhere to sticky surfaces and act as spacers preventing them from contacting each other and thus reducing the inter-particle forces and bulk powder cohesion. A question which naturally arises is how much flow-aid is needed to enhance the flowability to an optimum level. This work aims to establish a relationship between the degree of Surface Area Coverage (SAC) of flow-aids and the flowability, the latter as determined by a quasi-static shear cell method, as well as the angle of repose test and the FT4 powder rheometer. Glass beads of 90–150 μm sieve cut are made cohesive by silanising their surfaces with a commercial chemical reagent, Sigmacote® and are used as host particles. Two types of zeolite particles are used as flow aids. The mass fraction of the flow aids required to achieve a theoretical SAC of 1, 5, 10, 20, 50 and 100% is first estimated and then the host particles are coated in a pan mixer. The SAC is measured by Scanning Electron Microscopy, coupled with image analysis, and found to correlate well with the estimated value. The optimum surface coverage is found to be when SAC is 10–20%, as this provides the greatest flowability. An increase in SAC beyond this range leads to a gradual reduction in flowability.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Editors: |
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Copyright, Publisher and Additional Information: | © 2017 Published by Elsevier B.V. This is an author produced version of a paper published in Powder Technology. Uploaded in accordance with the publisher's self-archiving policy. |
Keywords: | cohesive, flowability, flow aids, processing, Surface area coverage, coating |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Engineering & Physical Sciences (Leeds) > School of Chemical & Process Engineering (Leeds) |
Funding Information: | Funder Grant number EPSRC EP/K503836/1 |
Depositing User: | Symplectic Publications |
Date Deposited: | 19 Sep 2017 09:23 |
Last Modified: | 18 Sep 2018 00:38 |
Status: | Published |
Publisher: | Elsevier |
Identification Number: | 10.1016/j.powtec.2017.09.013 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:121325 |